Currently, plants are known for feeding to a bag-filling machine groups of rolls of paper coming from a production line or from packaging lines. The rolls are usually arranged with their axes horizontally and in single file and in contact with one another. The rolls are rotated through ninety degrees about an axis that is horizontal and orthogonal thereto. The rotation is performed by a carousel with horizontal axis, equipped with blades of length correlated to the dimensions of the products to be treated, which pick up the rolls from the feed line and raise them, subjecting them to a rotation of 90° about the axis of said carousel, so as to set the rolls with a vertical axis and feed them in an upper station, where the rolls themselves are accumulated in a pre-set amount and then are moved away in the right phase by a pusher that operates parallel to the axis of the carousel or else by a pusher that operates with a movement orthogonal to the axis of said carousel and when this is moving, so as to eliminate any dead times.
This latter solution is suited for continuous-cycle operation but has speed limitations due to the friction of mutual detachment of the rolls when they are gripped by the blades of the raising carousel and to the friction between blades and rolls when the latter accumulate in the upper station, with the risk of being damaged or tipped over forwards by the thrust of said blades. Said blades are usually in a fixed radial position with respect to the carousel.
As an alternative to the above systems, the rolls, either single or pre-packaged and arranged with horizontally oriented axes, are caused to perform a descending movement by exerting a thrust and by gravity within guides shaped like the sector of a circle and having a curvature of ninety degrees, at the end of which the rolls are arranged with their axes set vertically and are moved away by a reciprocating pusher, which transfers them into an accumulation station, from which the groups of rolls are then moved away by continuous pushers, constituted, for example, by pusher cross members moved by parallel conveyors. Also this solution has limits due to the friction of mutual detachment of the rolls when they are moved away by the reciprocating pusher and limits due to the cyclic nature of operation of said pusher in so far as the flow of the rolls must stop both during the travel of the pusher forwards and during its return.
Consequently, the known art does not teach methods and apparatuses capable of handling the rolls delicately and prearranging them in a dynamic and fast way for feeding a continuous-operation and high-production bag-filling machine. The known art does not even teach solutions for a rapid adaptation of the means to the change of format of the products and to the number of the rows of said products that are to be treated each time.